<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>lifestyle</title>
</head>

<body>
  <div id="app">
    x: {{ position.x }} <br>
    y: {{ position.y }}
  </div>
  <script type="module">
    import { createApp, reactive, onMounted, onUnmounted } from './node_modules/vue/dist/vue.esm-browser.js'

    function useMousePosition() {
      // 第一个参数 props
      // 第二个参数 context，attrs、emit、slots
      // 创建响应式对象（返回proxy对象）
      const position = reactive({
        x: 0,
        y: 0
      })

      const update = e => {
        position.x = e.pageX
        position.y = e.pageY
      }

      onMounted(() => {
        window.addEventListener('mousemove', update)
      })
      // 相当于destroyed
      onUnmounted(() => {
        window.removeEventListener('mousemove', update)
      })
      return position
    }

    const app = createApp({
      setup () {
        const position = useMousePosition()

        return {
          position
        }
      },
      mounted() {
        this.position.x = 100
      }
    })
    // 打印查看app
    console.log(app)

    app.mount('#app')
  </script>
</body>

</html>